(1) Field of the Invention
The present invention relates to underwater communication and more particularly to a system and method for generating an underwater acoustic waveguide to guide acoustic energy between a source and a receiver.
(2) Description of the Prior Art
It is known in the art that the attenuation of acoustic energy in water presents problems in long distance underwater communications. While very low frequency acoustic energy can be propagated over long distances, the underwater environment is “noisy” in these bands.
At higher frequencies, the attenuation is such that high power is needed to generate sufficiently strong acoustic energy needed for communication. For example, spherical spreading losses lead to approximately 66 decibel (dB) attenuation at a range of approximately 2000 meters.
It is also known in the art that acoustic energy confined to a waveguide can travel over large distances without spherical spreading losses.
What are therefore needed are a system and method for generating an underwater waveguide such that acoustic energy can be transmitted through the waveguide over long distances. Accordingly, the waveguide needs to be stable over time and needs to extend over long distances to provide underwater communication between widely separated platforms. For efficiency, the power requirements for generating the waveguide need to be minimized.